This invention relates to an assembly consisting of a tapered bushing and a toothed wheel, with a preferred direction of rotation. More particularly, this invention relates to an assembly, which allows the bushing and the toothed wheel to be mated together, or separated, using a threaded rod inserted and tightened from either side of the assembly.
Assemblies using conventional tapered bushings to fasten pulleys, sheaves, or gears to hafts are widely used. Tapered bushings use less space on an axial shaft than other types of bushings and are favored for this reason. For example, the QD bushing and wheel assembly requires additional axial space due to the flange area of the bushing that protrudes from the ace of the wheel.
Assemblies using tapered bushings have a female mating surface on the wheel and a male mating surface on the bushing. The tapered bushing is axially split and contractible about the shaft which it receives. As the male mating surface of the bushing is mated with the female mating surface of the wheel, the bushing contracts around the shaft. Thus, by mating the bushing and the wheel, the bushing becomes affixed to the shaft and the wheel affixed to the bushing. However, difficulty is often encountered in the process of mating the bushing and the wheel, and in separating the bushing from the wheel once mated.
Prior art improvements to these assemblies have focused on designs that aid in mating or separating the bushing and the wheel. In U.S. Pat. No. 2,402,743 entitled xe2x80x9cMOUNTING FOR SHEAVES, ETC.xe2x80x9d, granted Jun. 7, 1944, the inventor used a plurality of screws parallel with the hub axis for effecting wedging of the bushing between the hub and the shaft. As the screws are tightened sufficiently their heads abut against the bushing shoulders and further entry of the screws into the hub wedges the bushing between the hub and the shaft. However, in this invention the screws are only inserted from one side of the assembly.
As the use of the invention of U.S. Pat. 2,402,743 became more widespread, difficulties arose when the assembly was to be mounted in close proximity to another item, such as a drive motor or another bushing wheel assembly. This problem became more apparent to the inventor with the use of assemblies with toothed wheels having a preferred direction of rotation, such as assemblies for use with the Eagle PD(trademark) belt described in U.S. Pat. 5,209,705. When affixing these assemblies to a shaft to rotate in the preferred direction, the face of the assembly containing the screws may be in close proximity to another containing the screws may be in close proximity to another item. This results in great difficulty in tightening the screws.
U.S. Pat. No. 3,682,505 entitled xe2x80x9cMEANS FOR MOUNTING SHEAVES, ETC.,xe2x80x9d granted Aug. 8, 1972, describes an attempt to overcome this problem. With the mounted sheave system disclosed in this patent, a plurality of longitudinal bores are formed in the assembly. Each bore is aligned and in communication with a screw hole. Each screw for use in the assembly includes a socket or slotted portion at the end for engaging a driving tool which can be inserted into either the bore or the hole to tighten the screw from either side of the assembly. A disadvantageous limitation of this system is that the bolts can only be inserted from one face of the assembly. Access to insert or remove these bolts may be limited when the face of the assembly containing the holes is placed in close proximity to another item.
U.S. Pat. 2,763,158 and 3,851,977 also describe similar bushing and sheaves.
The toothed wheel and tapered bushing assembly of the invention addresses the problem of the prior art that occurs when the prior art assembly is mounted in close proximity to another item. Since access to the screws, used to mate or separate the bushing and the wheel, may be limited, this invention allows the screws, or threaded rods, to be inserted and tightened from either face of the assembly. This invention allows assembly inventories to be half that needed in the past because the assembly can be used regardless of which side of the assembly is in close proximity to the other item.
This invention relates to an assembly 10 of a toothed wheel 12 and a tapered bushing 14. The toothed wheel 12 has a tapered hole 16 forming at least one tapered surface 18 in the wheel 12. The tapered hole 16 also forms a first and a second opening, the first opening W1 being larger than the second opening W2. The tapered bushing 14 has at least one tapered surface 20. The bushing tapered surface 20 is capable of mating relationship with the wheel tapered surface 18. The assembly 10 has a first face 22 and a second face 24 spaced apart from one another along an axis. When the tapered surfaces of the bushing 14 and the wheel 12 are in mated relationship, the first opening W1 of the wheel hole 16 is in proximity to the first face 22 of the assembly 10 and the second opening W2 of the wheel hole 16 is in proximity to the second face 24 of the assembly 10. The assembly 10 also has a first hole or set of holes H1, respectively, for receiving a threaded rod 26. This hole or set; of holes H1 extends at least partially along the mating surfaces from the first face 22 of the assembly 10 toward the second face 24 of the assembly 10. The holes H1 are formed in part by a groove 28 located in the toothed wheel 12 and in part by a groove 30 located in the bushing 14.
The toothed wheel 12 in the assembly of the invention has a preferred direction of rotation about its axis. The assembly 10 also has a second hole or set of holes H2, respectively, for receiving a threaded rod 26. These holes H2 extend at least partially along the mating surfaces from the second face 24 of the assembly 10 toward the first face 22 of the assembly 10. The holes H2 are formed in part by a groove 32 located in the toothed wheel 12 and in part by a groove 34 located in the bushing 14. The threaded rod 26 is able to interact with surfaces in or adjacent to the wheel and the bushing grooves of each hole. This interaction can cause the toothed wheel 12 and the bushing 14 to be moved in an axial direction with respect to each other when the threaded rod 26 is threaded into either the first or second hole or sets of holes and is tightened.
For ease of understanding this disclosure, the following terms are disclosed.
xe2x80x9cAxialxe2x80x9d or xe2x80x9caxiallyxe2x80x9d means the lines or directions that are parallel to the axis of rotation of the toothed wheel and bushing assembly 10.
xe2x80x9cTaperxe2x80x9d or xe2x80x9ctaperedxe2x80x9d means that an item gradually narrows toward one end.